This invention pertains generally to underwater discharge systems and more particularly, to systems that are employed to discharge an effluent overboard from a floating vessel, underwater, to a remote location.
The concept of offshore siting of nuclear power generating facilities has been considered for some time. The worsening trends in finding suitable land sites along the coast, power plant cost escalation, schedule delays, the growing concern over the environmental impact of nuclear power generating stations and the desire for standardization to facilitate the licensing process have lent impetus to a serious consideration of offshore siting. The development of a floating nuclear plant requires that new design considerations be addressed to accommodate the unique environment in which the plant is to be situated. One such consideration is the mechanism to be employed to carry the cooling water discharge from the plant condenser, underwater, to a location in effect "downstream" of the cooling water intake.
Since floating nuclear plants will be subject to large movements due to tide, wind and wave action, a device in the overboard condenser coolant discharge piping system which will permit such motion, while at the same time maintaining the integrity of the fluid carrying system, is required. Some additional constraints on the system are that it be leakage free, not serve as an impediment to service barge traffic or the barge loading dock, and that it minimize pumping, maintenance and installation requirements.
One proposed system employs a gooseneck piping arrangement with the outlet end submerged. However, analysis has shown this configuration presents high pump power requirements, large weight additions, and unstable flow and support problems.
A second such system, which provides an improvement to the gooseneck piping system, is described in U.S. patent application Ser. No. 928,948, filed July 28, 1978. This latter system employs a submerged piping arrangement constructed with neutral buoyancy, which enables it to be self supporting and flexible to accommodate barge motion. However, the system does not overcome the cost of substantially large piping runs that will be required through the barge to transport the coolant overboard.
Accordingly, an improved piping arrangement is desired for transporting the condenser coolant discharge of a floating nuclear plant to an external location downstream of the condenser inlet that overcomes the aforestated deficiencies of previously proposed systems.